Oil is used as a lubricant in engines to allow engine parts to slide freely and easily, with reduced friction. Notwithstanding the use of lubricants having high lubricity there continues to be some cutting and tearing between the metal in the internal engine components such as the turbocharger, the camshaft, the crankshaft, and the rocker assembly, to name a few. It has been known for some time that the greatest wear on internal engine component parts is during the initial moments during ignition cranking and engine start-up. At that time, the oil pressure in the engine has not built up sufficiently to provide oil to these parts. Consequently, for those first moments there can be essentially the bare metal rubbing against the bare metal. Over time, this is very detrimental to internal engine components.
One solution to this problem is to introduce chemical additives to the oil which cling to the walls of the cylinders after the engine is shut off. When the engine is next engaged, the cylinder walls have some lubricant present to protect them and the pistons from excessive wear and tear.
Another approach is a pre-lubrication system as disclosed in U.S. Pat. No. 4,502,431 to John F. Lulich. This patent discloses a novel system for introducing oil to the engine prior to cranking and start-up. This method has provided significant reduction in engine wear. However, the modifications required to the engine are applicable principally to large diesel engines.
A variety of additional approaches have been previously attempted to alleviate this problem, one such approach being exemplified by U.S. Pat. Nos. 3,583,525; 3,583,527; 3,722,623; 3,917,027; 4,061,204; 4,094,293; 4,112,910; 4,157,744 and 4,199,950. These patents generally teach that the problem relates to a lack of lubrication at start-up, and disclose systems having an auxiliary oil accumulator which through appropriate valving bleed off store a portion of the oil supply during normal engine operation and release it under pressure to the engine prior to or at the time of the next restart. While the release of a lesser quantity of oil from an auxiliary oil accumulator might yield some benefit, there would still remain a period during which the engine was cycling prior to the time that full lubrication was provided the moving parts. Because space is already at a premium in engine compartments, it is unacceptable to include an auxiliary oil accumulator having a sufficiently large volume, and even if it were practical, use of such a large volume accumulator would tend to create large variations in the oil supply of the engine. Finally, inclusion of a pressurized oil reservoir within a hot engine compartment presents an unacceptable safety hazard due to the possibility of a rupture and spray of flammable liquid thereover.
Another approach is exemplified by U.S. Pat. Nos. 4,058,981 and 4,126,997, which disclose that inadequate start-up lubrication is the cause of the problem and teach a valve system which initially routes engine oil to more critical engine components such as the turbocharger and crankshaft bearings upon start-up, and thereafter to less critical engine components. This approach is beneficial, but since it does not become operative until engine parts begin relative movement, premature wear of critical engine elements is still a problem.
Another approach, exemplified by U.S. Pat. No. 3,045,420 involves the use of a plurality of oil pumps, each supplying oil to separate engine lubrication systems. The pump which supplies oil to the turbocharger unit of the engine is actuated prior to combustion, continues during engine operation, and continues to operate for a brief period after engine shutdown to protect the relatively sensitive high speed turbocharger bearings. This system may be beneficial in extending the turbocharger life expectancy, but it does not protect other vital engine components, it introduces substantial complexity into the lubrication system of the engine, and failure of the turbocharger pump would lead to turbocharger failure within seconds.
Finally, manufacturers of internal combustion engines are known to attempt to minimize the problem by incorporating relatively large capacity oil pumps in the lubricating system in order to minimize the period between initial combustion and when engine oil pressure reaches its normal operating level. This approach has not had the desired result of reducing wear and it introduces unnecessary weight, size and expense to the engine assembly.
Accordingly, it is an object of the present invention to provide pre-compression/combustion protection to the parts of an internal combustion engine as well as during the first few moments of operation.
Another object of the present invention is to introduce via the oil filter mechanisms, a pump and linkage assembly that raises the oil pressure of an engine before it is allowed to crank to start.